ng-if(Angularjs)不工作

<div ng-if="'done'={{task_detail.status}}">
    <b>Status :</b> 
    <p class="label label-success">{{task_detail.status}}</p>
    <br>
    <br>
    <div class="progress progress-striped">
        <div class="progress-bar" role="progressbar" aria-valueNow="100" aria-valuemin="0" aria-valuemax="100" style="width:{{task_detail.percentage_finished}}%">
            <span class="sr-only">{{task_detail.percentage_finished}}% Complete</span>
        </div>
    </div>
</div>

这是我渲染的json数据：

{
     "id": 1,"title": "Launch an EC Instance","desc": "Needed an EC instance to deploy the ccr code","status": "done","percentage_finished": 100
 }

问题：HTML视图不可见，因为控件在ng-if内不移动。
语法是否正确？